This invention relates to a machine for the processing of sheet metal workpieces and which incorporates a bending station for bending a workpiece and a joining station for welding adjacent surfaces of the bent workpiece.
A bending machine having a movable positioning system for the workpiece is described in European Patent A-0 650 782. Such a machine may include a programmable controller for controlling movement and actuation of the operational components.
In modern production operations, it is often necessary to process workpieces in different ways depending upon their type and design. For example, in today""s flexible manufacturing environment, sheet metal products are first bent or folded and subsequently joined in an assembly operation. A machine capable of these two processing modes is described in Japanese Patent A-02274316. That machine incorporates a bending tool consisting of an upper bending tool and a lower bending die, as well as an integral, movable, motor-driven welding head. The welding head serves to produce weld joints on a workpiece clamped between the upper and lower bending dies of the machine.
It is an object of the present invention to provide a novel machine providing bending and welding operations in separate stations and enabling facile processing of the workpiece.
It is also an object to provide such a bending and welding machine which can be fabricated relatively economically and which is relatively simple and reliable in operation.
It has now been found that the foregoing and related objects may be readily attained in a sheet metal forming machine tool having a bending station including a bending tool and a cooperating bending die, the tool and die being relatively movable to bend a sheet metal workpiece disposed therebetween. This station also includes workpiece positioning means with at least one positioning stop for positioning the workpiece between the bending tool and die, first drive means for moving the positioning stop, and second drive means to effect relative movement of the bending tool and die to bend the workpiece to provide at least one pair of adjacent edge surfaces.
The machine tool also has a joining station which includes workpiece positioning means and at least one welding head for welding adjacent edge surfaces of the bent workpiece. The welding head is movable with the positioning stop along adjacent edge surfaces of the workpiece. Control means is provided for the second drive means to effect relative movement of the bending tool and die, for the first drive means for the positioning stop to effect movement of the welding head along the adjacent edge surfaces of the workpiece, and for the welding head to supply energy thereto to produce a weldment between the adjacent edge surfaces of the workpiece.
The bending tool is disposed above the bending die, and the bending tool is seated in an upper tool mount vertically movable relative to the bending die for bending the workpiece. The workpiece positioning means for holding the workpiece in a fixed position during the welding operation includes a workpiece holder which can be raised and lowered with the upper tool mount of the bending station whereby the workpiece can be positioned during welding.
Preferably, the tool mount of the bending station extends beyond the bending station to the joining station, and the movable workpiece holder of the joining station is coupled to the upper tool mount. The vertically movable workpiece holder of the joining station is exchangeably coupled to the upper tool mount, and the workpiece holder includes an angle section to clamp the workpiece in the area of the fold line.
Desirably, the bending die of the bending station is supported on a machine platen which extends beyond the bending station to the joining station, and the platen serves as a support for the workpiece and cooperates with the vertically movable workpiece holder to clamp the workpiece therebetween.
A robot may be included for the transport of the workpiece between the bending station to the joining station.
The first drive means for the positioning stop of the bending station is operative to move the welding head in a controlled manner relative to the workpiece during the execution of the welding operation.
In a preferred embodiment, the positioning stop is mounted on a backstop carrier movable in a controlled manner by the first drive means and the welding head can be moved in combination with the backstop carrier. Desirably, the welding head is detachably coupled to one of the positioning stop and the backstop carrier, and it may be adjustably positioned on the positioning stop or on the backstop carrier.
The welding head and power supply comprise a laser welding system which includes a laser beam generator and a flexible fiber optic cable between the generator and the welding head. It will be appreciated that machine tools designed in accordance with this invention obviate the need for complex engineering measures and control devices which would otherwise be necessary for precise positioning and movement of the joining system or of the die mount raising and lowering mechanism.
The upper die mount of the bending station is utilized for supporting the vertically movable workpiece holder of the joining station. The mounting system permits the easy exchange of the workpiece holder which is supported on the upper die mount in the case of wear and tear or damage or for adapting the overall system to different processing conditions. The machine platen performs a supporting function for both the bending and the joining stations.
The workpieces being processed can be transported from the bending station to the joining station, or vice versa. Although this can be done manually, preference is given to the use of at least one robot for performing this function. Moreover, in the majority of cases, practical considerations dictate that the joining operation follow the bending of the workpiece.
An enhanced implementation of the invention provides for coupling of the movement of the joining systems on the one hand and of the positioning backstops and/or backstop mounts on the other. In this case, the joining system may be directly supported on a positioning backstop or on a backstop mount. If appropriately configured, it is possible for a positioning backstop supporting a joining system to perform its intended function of aligning workpieces to be bent without any interference by the joining system. In this context it may be desirable to mount the joining system on the positioning backstop in a manner which permits movement relative to the latter. This makes it possible for the joining system, while not in use, to be moved along the positioning backstop into an out of the way position, i.e., away from the workpiece holder so as not to interfere with the workpiece alignment. Corresponding provisions can be made in such cases where a joining system is directly supported by a backstop mount.
The positioning backstop or the backstop mount of the bending station can be connected to or disconnected from the joining system in an on-demand fashion. For example, if the joining system is not needed for one or several processing cycles, it can be disconnected from the positioning backstop and/or backstop mount prior to the processing operation. Especially in cases where the joining system is not to be used for an extended period of time, it can be moved into the out of the way position before it is disconnected from the positioning backstop or backstop mount. Then, when needed again, the joining system can be retrieved from that parked position by the positioning backstop and/or backstop mount.